create-load-tests

name	create-load-tests
description	Create or extend k6 load tests for this BFF template. Use when user asks for HTTP/gRPC performance scenarios, thresholds, custom metrics, or environment-driven load profiles in tests/LoadTests.

Create Load Tests (k6)

Create or update k6 scripts for HTTP and gRPC endpoints, with reusable environment-based settings and meaningful thresholds.

When to use

Activate this skill when the user asks to:

• add load tests for a new endpoint
• tune VUs/duration/thresholds
• add custom metrics (counter, trend, rate)
• validate throughput/latency behavior under load

Target files

• tests/LoadTests/scriptHttp.js — HTTP scenarios using k6/http; currently has get_order scenario hitting GET /orders/1
• tests/LoadTests/scriptGrpc.js — gRPC scenarios using k6/net/grpc; currently has get_order scenario invoking order.OrderService/Get
• tests/LoadTests/protos/*.proto — proto definitions loaded by the gRPC client (currently order.proto)

k6 conventions in this template

• Keep options.scenarios and options.thresholds explicit.
• Support env-driven test profile: VUS (default 10), DURATION (default '60s'), GRACEFUL_STOP (default '10s'), WEBAPP_URL (default https://localhost:7175), WEBAPP_GRPC_URL (default localhost:7175).
• Per-scenario custom metrics follow the naming pattern <scenario>_requests_total (Counter), <scenario>_response_time (Trend), <scenario>_success_rate (Rate).
• HTTP headers always include correlationId: crypto.randomUUID(), Accept: application/json, CacheEnabled: false.
• gRPC client is instantiated at module level; client.load([], './protos/<file>.proto') before export function.
• HTTP thresholds: http_req_duration p(95) < 500, http_req_failed rate < 0.1.
• gRPC thresholds: grpc_req_duration p(95) < 100.
• Keep checks focused on status and minimal payload validity.

Workflow

1. Identify target endpoint(s) and success criteria.
2. Add/update scenario function(s) in scriptHttp.js and/or scriptGrpc.js.
3. Add/update thresholds for latency, errors, and throughput.
4. Add/update proto contracts under tests/LoadTests/protos when needed.
5. Run the k6 script and tune thresholds.

Done checklist

• Scenario names and metrics are descriptive
• Thresholds reflect realistic SLO expectations
• Env vars control VUs/duration and base URLs
• Checks validate status + key payload behavior
• Script runs successfully with full summary

Practical examples

Example 1 — New HTTP scenario

User asks:

• "Create a k6 scenario for POST /orders"

Expected file changes:

• tests/LoadTests/scriptHttp.js (updated)

Real project reference:

// Pattern from tests/LoadTests/scriptHttp.js
const createOrderRequestsCounter = new Counter('create_order_requests_total');
const createOrderResponseTime = new Trend('create_order_response_time');
const createOrderSuccessRate = new Rate('create_order_success_rate');

export function createOrder() {
  createOrderRequestsCounter.add(1);

  const payload = JSON.stringify({
    correlationId: crypto.randomUUID(),
    description: 'Load test order',
    items: [{ name: 'Item 1', description: 'Desc', value: 9.99 }]
  });

  const res = http.post(`${webappUrl}/orders`, payload, {
    headers: {
      'Content-Type': 'application/json',
      'correlationId': crypto.randomUUID(),
      'CacheEnabled': 'false'
    }
  });

  createOrderResponseTime.add(res.timings.duration);
  const ok = check(res, {
    'status is 200': (r) => r.status === 200,
    'has data': (r) => JSON.parse(r.body)?.data != null
  });
  createOrderSuccessRate.add(ok);
  sleep(1);
}

Acceptance checks:

• Scenario has explicit executor, VUs, duration driven by env vars
• Adds Counter, Trend, and Rate metrics with create_order_ prefix
• Adds checks for status 200 and key response fields

Example 2 — Tune thresholds for existing scenario

User asks:

• "Make GET /orders load test stricter for p95 latency"

Expected file changes:

• tests/LoadTests/scriptHttp.js (updated)

Real project reference:

// Current threshold in scriptHttp.js:
get_order_response_time: ['p(95) < 500'],
// After tightening:
get_order_response_time: ['p(95) < 200'],

Acceptance checks:

• Threshold keys map to existing metric names (get_order_response_time, etc.)
• Threshold values match intended SLO
• Script remains runnable with env overrides

Example 3 — Add gRPC performance path

User asks:

• "Load test CreatePayment gRPC method"

Expected file changes:

• tests/LoadTests/scriptGrpc.js (updated)
• tests/LoadTests/protos/payment.proto (add if not present — mirrors src/Contracts/Protos/payment.proto)

Real project reference:

// Pattern from tests/LoadTests/scriptGrpc.js
client.load([], './protos/payment.proto');

const createPaymentCounter = new Counter('create_payment_requests_total');
const createPaymentResponseTime = new Trend('create_payment_response_time');
const createPaymentSuccessRate = new Rate('create_payment_success_rate');

export function createPayment() {
  createPaymentCounter.add(1);
  client.connect(webappUrl, { plaintext: false });

  const start = Date.now();
  const response = client.invoke('Protos.PaymentService/Create', {
    order_id: 1,
    amount: 99.99,
    correlation_id: crypto.randomUUID(),
    currency: 'USD',
    payment_method: 'credit_card'
  });
  createPaymentResponseTime.add(Date.now() - start);

  const ok = check(response, {
    'status is OK': (r) => r && r.status === grpc.StatusOK,
    'success': (r) => r.message?.success === true
  });
  createPaymentSuccessRate.add(ok);
  client.close();
  sleep(1);
}

Acceptance checks:

• gRPC client loads correct proto (payment.proto) and invokes Protos.PaymentService/Create
• Checks validate grpc.StatusOK and message.success === true
• Scenario reports response-time and success-rate metrics